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1.
Yield, dry matter production, nitrogen (N) uptake and nitrogen use efficiency (NUE) of Bangladesh Rice Research Institute (BRRI) dhan29 were investigated during two consecutive dry (Boro) seasons of 2009–10 and 2010–11. The experiments were set up in a randomized complete block design with three replication having six nitrogen (N) levels of 0, 40, 80 120, 160 and 200 kg ha?1. Nitrogen fertilization increased yield characters, dry matter production and N uptake. The economic optimum rate of N was 166 and 155 kg ha–1 in first and second year, respectively, with corresponding yield of 7.1 and 6.5 t ha?1. NUEs were higher in the first year, decreased with increasing N rates in most cases. Gross return over fertilizer reached the highest Tk 692 in 2009–10 and Tk 489 in 2010–11 with 160 kg N ha–1. The results suggest that BRRI dhan29 should receive an average of 160 kg N ha?1 for economic optimum yield.  相似文献   

2.
Data from a 49-year-long organic–mineral fertilization field experiment with a potato–maize–maize–wheat–wheat crop rotation were used to analyse the impact of different fertilizer variations on yield ability, soil organic carbon content (SOC), N and C balances, as well as on some characteristic energy balance parameters. Among the treatments, the fertilization variant with 87 kg ha?1 year?1 N proved to be economically optimal (94% of the maximum). Approximately 40 years after initiation of the experiment, supposed steady-state SOC content has been reached, with a value of 0.81% in the upper soil layer of the unfertilized control plot. Farmyard manure (FYM) treatments resulted in 10% higher SOC content compared with equivalent NPK fertilizer doses. The best C balances were obtained with exclusive mineral fertilization variants (?3.8 and ?3.7 t ha?1 year?1, respectively). N uptake in the unfertilized control plot suggested an airborne N input of 48 kg ha?1 year?1. The optimum fertilizer variant (70 t ha?1 FYM-equivalent NPK) proved favourable with a view to energy. The energy gain by exclusive FYM treatments was lower than with sole NPK fertilization. Best energy intensity values were obtained with lower mineral fertilization and FYM variants. The order of energy conversion according to the different crops was maize, wheat and potato.  相似文献   

3.
A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha?1), P (41 kg ha?1) and K (227 kg ha?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.  相似文献   

4.
Abstract

Effective soil diagnostic criteria for exchangeable potassium (Ex-K) combined with inorganic potassium (K) application rates were developed to lower K input in forage corn (Zea mays L.) production using experimental fields with different application rates and histories of cattle manure compost. Two corn varieties, ‘Cecilia’ as a low K uptake variety and ‘Yumechikara’ as a high K uptake variety, were selected from among 20 varieties and tested to make diagnostic criteria for K fertilization applicable to varieties with different K uptakes. The K uptakes increased from 96 to 303 kg K ha?1 for ‘Cecilia’ and from 123 to 411 kg K ha?1 for ‘Yumechikara’ with increasing Ex-K content on a dry soil basis from 0.11 to 0.92 g kg?1 with no inorganic K fertilizer application. The K uptake by corn for achieving the target dry matter yield of 18 Mg ha?1 was estimated to be approximately 200 kg K ha?1 in common between the two varieties. Yields of both varieties achieved the target yield at an Ex-K content of approximately 0.30 g kg?1 with no K fertilization, although ‘Yumechikara’ reached the target yield at a lower Ex-K content. At the low Ex-K content of 0.1 g kg?1, inorganic K fertilizer application at 83 kg K ha?1 was needed to gain the target yield, and apparent K recovery rate for K fertilizer was calculated to be 70% for both varieties. The K uptakes for gaining the target yield by the K fertilization were lower than that by soil K supply. Based on these results, diagnostic criteria of Ex-K and inorganic K application rates were set up as follows: at an Ex-K content of < 0.15 g kg?1, inorganic K fertilizer is applied at 83 kg K ha?1 (100 kg ha?1 as potassium oxide (K2O) equivalent); at an Ex-K content of 0.15–0.30 g kg?1, the application rate is reduced to 33 kg K ha?1 (40 kg K2O ha?1); at an Ex-K content of ≥ 0.30 g kg?1, inorganic K fertilizer is not applied because of sufficient K in the soil. Additionally, we propose that cattle manure compost be used to supplement soil K fertility.  相似文献   

5.
Besides being an essential macronutrient for plant growth, potassium (K) also acts as a stress-relieving agent against various biotic and abiotic stresses, especially water stress. An experiment consisting of three lowland Thai rice varieties (Pathumthani 1, RD57, RD41), two cultivation methods [dry direct seeding (DDS), transplanting (TP)] and four K doses (0, 80, 120,160?kg ha?1) under alternate wetting and drying (AWD) water regime was conducted to investigate the impact of K and cultivation method on lowland rice varieties subjected to AWD. Pathumthani 1 had significantly higher grain yield at the 120?kg K ha?1 compared with all other K doses. RD57 and RD41 had maximum grain yield at the 80 and 120?kg K ha?1, respectively, which was significantly higher than the control; however, grain yield among different K doses was mostly similar for RD57 and RD41. K application at the rate of 120?kg ha?1 for Pathumthani 1 and 80?kg ha?1 for RD57 and RD41 could be a feasible option. The performance of DDS and TP was better at the 80 and 120?kg K ha?1, respectively. Application of K at the optimum dose with proper selection of variety and cultivation method could help in sustainable rice production.  相似文献   

6.
Sulfur (S) and zinc (Zn) deficiencies are frequently reported in Bangladesh rice paddy. However, its effects on rice productivity and soil fertility need to be reevaluated as sulfur oxides (SOx) and heavy metals are increasingly emitted to the environment in the recent years. To examine the long-term effects of S and Zn fertilization on rice yield and nutrient efficiency, the standard fertilization plot of nitrogen, phosphorus, potassium, sulphur, and zinc (NPKSZn) was installed in a typical double rice cropping paddy at the Bangladesh Rice Research Institute (BRRI) farm in 1985. The recommended treatment (NPKSZn) and the comparison treatments (NPKZn and NPKS) were selected for calculating S and Zn efficiencies. The same levels of chemical fertilizers in NPKSZn treatment were applied with the rates of N-P-K-S-Zn as 80–25–35–20–5 kg ha?1 and 120–25–35–20–5 kg ha?1 in the wet and dry seasons, respectively. The changes in rice productivity, as well as S and Zn fertilization efficiencies, were monitored for 23 years. Sulfur fertilization significantly increased the mean grain and straw yields by around 13% in the wet season and only 4–5% in the dry season. The mean S fertilization efficiencies were 9.3% and 5.3% in the wet and dry seasons, respectively. Sulfur fertilization efficiency was relatively high until 1997 (the 13th year after the installation). Thereafter, however, S fertilization did not increase rice productivity or efficiency, regardless of the season. Also, Zn fertilization did not result in a significant increase in rice productivity, and its fertilization efficiency was similar level with a mean of 1.2%, irrespective of the season. This study revealed that S and Zn fertilization may no longer be required to increase rice productivity in Bangladesh paddy soil due to fast industrialization and urbanization.  相似文献   

7.
Excessive and inappropriate use of fertilizers is a key factor of low sugarcane yield and degradation of soil. A two-year (2013–14 and 2014–15) field study was conducted to assess the impact of combined application of organic and inorganic fertilizers on sugarcane at research farm of Shakarganj Sugar Research Institute, Jhang, Pakistan. Experiment was conducted under randomized complete block design with three replications. Treatments were used as control (no exogenous application), spent wash (160 t ha?1), (nitrogen, phosphorus and potassium) NPK (168:112:112 kg ha?1), spent wash (120 t ha?1) + NPK (42:28:28 kg ha?1), spent wash (80 t ha?1) + NPK (84:56:56 kg ha?1), spent wash (40 t ha?1) + NPK (126:84:84 kg ha?1), and spent wash (160 t ha?1) + NPK (42:28:28 kg ha?1). Application of spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1 resulted maximum crop growth rate (11.35 g m?2 d?1), leaf area index (7.78), and net assimilation rate (2.53 g m?2 d?1). Maximum number of millable canes (14), weight per stripped cane (0.90 kg), stripped cane yield (117.60 t ha?1) and unstripped cane yield (141.25 t ha?1) were observed with spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1, followed by sole fertilizer application @ 168:112:112 kg NPK ha?1 and spent wash @160 t ha?1 + NPK @ 42:28:28 kg ha?1. Similar trend was observed regarding quality parameters. The maximum benefit–cost ratio (1.80) was achieved with integrated application of spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1.  相似文献   

8.
Rising soil salinity has been a major problem in the soils of Egypt in recent decades. Potassium fertilization and salicylic acid (SA) play an important role in promoting plants to tolerate salt stress and increased the yield of sugar beet crop. A field experiment on sugar beet (Beta vulgaris L.) grown on saline soil was carried out during 2014 growing season in Port Said Governorate, Egypt, to study the effect of potassium fertilization of the soil at applications of 0, 100, 150, and 200 kg potassium (K) ha?1 and foliar spray of SA by solution of 1000 mg L?1, twice (1200 L ha?1 each time) on yield and nutrient uptake. Application of 200 kg K ha?1 in combination with salicylic foliar spray gave the highest root length, root diameter, shoot and root yield, sucrose, juice purity percentage, gross sugar yield, and white possible extractable sugar, nitrogen (N), phosphorus (P), and potassium (K) content, and uptake of sugar beet. The highest increase in sucrose (20%) as well as white possible extractable sugar (184%) was obtained by 200 kg K ha?1 in combination with salicylic foliar spray compared with untreated soil with potassium fertilization and without salicylic foliar spray.  相似文献   

9.
This study investigated the impacts of organic- and clay-based soil amendments, and their combinations on crop water productivity (CWP) using maize as a test crop. On-station field trials were established over two consecutive years at the Naphok and Veunkham sites in Laos. At each site, 10 treatments were applied in a randomized complete block design with three replications. The treatments were control, rice husk biochar (10 t ha?1), bentonite clay (10 t ha?1), compost (4 t ha?1), clay-manure compost (10 t ha?1), rice husk biochar compost (10 t ha?1), bentonite clay + biochar, bentonite-clay + compost, biochar + compost, and bentonite clay + biochar + compost. All treatments were applied in 2011. Significant (p < 0.05) treatment effects in CWP and growing period evapotranspiration were determined. At Naphok, differences between the amended and control plots in CWP varied between 0.1 and 0.6 kg m?3 in 2011 and from 0.1 to 0.4 kg m?3 in 2012, whereas differences at Veunkham varied between 0.3 and 1.0 kg m?3 in 2011 and from 0.05 to 0.29 kg m?3 in 2012. At both sites, CWP in 2012 was significantly lower than 2011. Our results illustrate that organic- and clay-based soil amendments improve CWP, indicating that soil-based interventions could be suitable options for improving agricultural productivity.  相似文献   

10.
ABSTRACT

Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ (subabul) green manuring along with zinc fertilization on water productivity and soil fertility in rice under rice–wheat cropping system at Indian Agricultural Research Institute, New Delhi, India. Sesbania incorporation recorded higher total water productivity (2.20 and 3.24 kg ha?1 mm?1), available soil nutrients, organic carbon, alkaline phosphatase activity, microbial biomass carbon and increased soil dehydrogenase activity by 39.6 and 26.8% over subabul and rice bean respectively. Among interaction of green manures and zinc fertilization, subabul × foliar application of chelated zinc-ethylenediaminetetraacetic acid at 20, 40, 60 and 80 days after transplanting recorded highest total water productivity (2.56 and 3.79 kg ha?1 mm?1). Foliar application of chelated Zn-EDTA at 20, 40, 60 and 80 days after transplanting recorded significantly higher water productivity than other Zn treatments, however it was statistically similar with foliar application of zinc at active tillering + flowering + grain filling. Sesbania × 5 kg Zn ha?1 through chelated Zn-EDTA, recorded highest available nitrogen, phosphorus, potassium, zinc, manganese, copper and iron than other green manure and Zn fertilization interactions, although it was statistically similar with rice bean × 5 kg Zn ha?1 through chelated Zn-EDTA as soil application. Sesbania × foliar application of 5 kg Zn ha?1 through chelated Zn-EDTA as soil application recorded highest soil enzymatic activities and microbial biomass carbon.  相似文献   

11.
A glass house study was conducted to investigate the accumulation of arsenic in tissues of five widely cultivated rice (Oryza sativa L.) varieties of Bangladesh namely BRRI dhan 28, BRRI dhan 29, BRRI dhan 35, BRRI dhan 36, BRRI hybrid dhan 1. Arsenic concentrations were measured in straw, husk and brown and polish rice grain to see the differential accumulation of arsenic among the rice varieties. The results showed that the concentrations of arsenic in different parts of all rice varieties increased significantly (p?<?0.05) with the increase of its concentrations in soil. The rice varieties did not showed significant differences in arsenic accumulation in straw, husk, brown and polish grain when the concentrations of arsenic in soil was low. However, at higher concentrations of arsenic in soil, different rice varieties showed significant differences in the accumulations of arsenic in straw, husk and grain. Significantly higher concentrations of arsenic in straw and husk of rice were observed in BRRI hybrid dhan 1 compared to those of other verities. The BRRI dhan 28 and 35 concentrated significantly higher amount of arsenic in brown and polish rice grain compared to those of other rice varieties. The results imply that arsenic translocation from root to shoot (straw) and husk was higher in hybrid variety compared to those of non-hybrid varieties. Arsenic concentrations in brown and polish rice grain of five rice varieties were found to follow the trend: BRRI dhan 28 > BRRI dhan 35 > BRRI dhan 36 > BRRI dhan 29 > BRRI hybrid dhan 1. The order of arsenic contents in tissues of rice was: straw > husk > brown rice grain > polish rice grain.  相似文献   

12.
Soil-test crop-response experiments on rice were conducted in the Bastar Plateau Agroclimatic Zone of Chhattisgarh during 2009–2011 to assess yield, soil, plant, and fertilizer nitrogen (N), phosphorus (P), and potassium (K) nutrient relationships and calibrate optimum fertilizer doses for attaining yield targets. Soil fertility status was poor to medium for N (194–283 kg ha?1) and P (7.53–19.66 kg ha?1), and medium to good for K (226–320 kg ha?1). Based on nutrient requirements (NR, kg q?1) and contributions from soil (CS, %), fertilizer (CF, %), and farmyard manure (CFYM, %), optimum fertilizer doses were derived. The fertilizer doses were validated for attaining yield targets of 5000 and 6000 kg ha?1 in farmer’s fields. Rice yield within 10% deviation was attained, which indicated that soil-test-based fertilizer dose was superior. This approach could be adopted for regions with similar soil and agroclimatic conditions in other parts of the world to increase rice yields.  相似文献   

13.
Disposal of oil palm fly ash (OPFA) into the environment causes environmental pollution. A field experiment was conducted to evaluate the effects of OPFA and mineral fertilizer on soil properties and yield of sweet corn. A total of six treatments were applied that included 2, 4, and 6 t ha–1 OPFA, 200 kg ha–1 nitrogen, phosphorus, and potassium (NPK), 100 kg ha–1 NPK + 2 t ha–1 OPFA as well as the control. A significant increase in soil pH and available P was observed with the sole OPFA treatments at 2, 4, and 6 t ha–1, while a significant increase in exchangeable cations [K, magnesium (Mg)] was detected only at the 6-t ha–1 OPFA treatment. The highest grain yield of 4220 kg ha–1 was obtained at the 100-kg ha–1 NPK + 2 t ha–1 OPFA-treated plots, which was statistically similar with the grain yield of 3800 kg ha–1 received at the 200-kg ha–1 NPK-treated plots. The practical implication of this study is that OPFA can be used as a liming material to increase soil pH and it has a synergetic effect in combination with inorganic fertilizer.  相似文献   

14.
An experiment was conducted to study the biochemical response of rapeseed (Brassica campestris L.) to sulphur (S) fertilization at grey terrace soil. There were five treatments: S0 (control), S1 (20 kg S ha?1), S2 (40 kg S ha?1), S3 (60 kg S ha?1) and S4 (80 kg S ha?1). Chlorophyll content in the leaf was determined at 30, 40, 50 and 60 days after emergence (DAE). The biochemical properties were found responsive to S. The highest chlorophyll content of mustard leaves was found in 60 kg S ha?1 at 50 DAE. The same treatment also showed the maximum N content in the leaves at 45 DAE. The highest oil content was recorded in 60 kg S ha?1. Other chemical characters such as acid value, peroxide and saponification values were lowest in 60 kg S ha?1 while iodine value was found highest in the same S level. Non-essential fatty acids such as palmitic, stearic and erucic acid were increased in the rapeseed with decrease in S level, whereas essential fatty acids were maximum in 60 kg S ha?1. Therefore, 60 kg S ha?1 can be recommended to produce quality rapeseed in grey terrace soil of Bangladesh.  相似文献   

15.
Macro-nutrients in soybean (Glycine max L. Merr.) have not been extensively researched recently. Concentrations and contents of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur (N, P, K, Ca, Mg, and S) were determined for three irrigated cultivars grown using the early soybean production system (ESPS) on two soils (a sandy loam and a clay) in the Mississippi Delta during 2011 and 2012. Data were collected at growth stages V3, R2, R4, R6, and R8. No change in macro-nutrients due to soil type or years occurred and modern cultivars were similar to data collected >50 years ago. Mean seed yield of 3328 kg ha?1 removed 194.7 kg N ha?1, 16.5 kg P ha?1, 86.0 kg K ha?1, 17.5 kg Ca ha?1, 9.0 kg Mg ha?1, and 10.4 kg S ha?1. Increased yields over the decades are likely due to changed plant architecture and/or pests resistance, improved cultural practices, chemical weed control, and increased levels of atmospheric carbon dioxide (CO2). Yield improvements by genetically manipulating nutrient uptake appear to be unlikely.  相似文献   

16.
Over the years, a scarcity of information on nutrient gains or losses has led to overemphasis being placed on crop yields and economic income as the direct benefits from fertilizer micro-dosing technology. There is increasing concern about the sustainability of this technology in smallholder Sahelian cropping systems. This study was designed in the 2013 and 2014 cropping seasons to establish nutrient balances under fertilizer micro-dosing technology and their implications on soil nutrient stocks. Two fertilizer micro-dosing treatments [2 g hill?1 of diammonium phosphate (DAP) and 6 g hill?1 of compound fertilizer Nitrogen-Phosphorus-Potassium (NPK) (15-15-15)] and three rates of manure (100 g hill?1, 200 g hill?1 and 300 g hill?1) and the relevant control treatments were arranged in a factorial experiment organized in a randomized complete block design with three replications. On average, millet (Pennisetum glaucum (L.) R.Br.) grain yield increased by 39 and 72% for the plots that received the fertilizer micro-dosing of 6 g NPK hill?1 and 2 g DAP hill?1, respectively, in comparison with the unfertilized control plots. The average partial nutrients balances for the two cropping seasons were ?37 kg N ha?1yr?1, ?1 kg P ha?1yr?1 and ?34 kg K ha?1yr?1 in plots that received the application of 2 g DAP hill?1, and ?31 kg N ha?1yr?1, ?1 kg P ha?1yr?1 and ?27 kg K ha?1yr?1 for 6 g NPK hill?1. The transfer of straw yields accounted for 66% N, 55% P and 89% K for removal. The average full nutrient balances for the two cropping seasons in fertilizer micro-dosing treatments were ?47.8 kg N ha?1 yr?1, ?6.8 kg P ha?1 yr?1 and ?21.3 kg K ha?1 yr?1 which represent 7.8, 24.1 and 9.4% of N, P and K stocks, respectively. The nutrient stock to balance ratio (NSB) for N decreased from 13 to 11 and from 15 to 12 for the plots that received the application of 2 g DAP hill?1 and 6 g NPK hill?1, respectively. The average NSB for P did not exceed 5 for the same plots. It was concluded that fertilizer micro-dosing increases the risk of soil nutrient depletion in the Sahelian low-input cropping system. These results have important implications for developing an agro-ecological approach to addressing sustainable food production in the Sahelian smallholder cropping system.  相似文献   

17.
On-farm research was conducted to investigate the effects of nitrogen (N) and compost (C) on yield and yield components of spring maize (Zea mays L.) under conventional and deep tillage system (T) at the research farm of the University of Agriculture, Peshawar, Pakistan, during spring 2013. The experiment was laid out in a randomized complete block design with split-plot arrangement, using three replications. Three compost levels (0, 1, and 2 t ha?1) and two tillage systems (conventional and deep tillage) were allotted to the main plot, whereas N levels (60, 90, 120, and 150 kg N ha?1) were allotted to subplots in the form of urea. Nitrogen and compost levels had significantly affected all the parameters. Plots treated with 150 kg N ha?1 increased ear length (31 cm), grains ear?1 (413), thousand-grain weight (240.2 g), grain yield (3097 kg ha?1), straw yield (9294 kg ha?1), harvest index (24.7 percent), and shelling percentage (81.7 percent). Compost applied at 2 t ha?1 increased ear length (32 cm), grains ear?1 (430), thousand-grain weight (242.3 g), grain yield (2974 kg ha?1), straw yield (8984 kg ha?1), harvest index (24.6 percent), and shelling percentage (83.2 percent). Tillage system had significant effect on all parameters except ear length and harvest index. Deep tillage system produced more grains ear?1 (365), thousand-grain weight (233.3 g), grain yield (2630 kg ha?1), straw yield (8549 kg ha?1), and shelling percentage (79.6 percent). It was concluded from the results that application of 120 kg N ha?1 + 2 C t ha?1 under a deep tillage system could improve spring maize yield and yield-contributing traits under semi-arid conditions.  相似文献   

18.
In order to investigate the changes in chlorophyll fluorescence, chlorophyll, relative water content (RWC) and forage yield of corn and sorghum under various irrigation regimes and combination treatments of barley residue, zeolite and superabsorbent polymer, an experiment was conducted over 2 years in Kerman, Iran. A randomized complete block design arranged in a factorial split was used with three replications. Two irrigation regimes of normal and drought stress based on 70 and 140 mm cumulative pan evaporation, respectively, and two plant species (corn and sorghum) as factorial combinations were compared in the main plots. Five treatments, (1) 10 t ha?1 zeolite + 4.5 t ha?1 residue, (2) 60 kg ha?1 superabsorbent + 4.5 t ha?1 residue, (3) 5 t ha?1 zeolite + 30 kg ha?1 superabsorbent + 4.5 t ha?1 residue, (4) 4.5 t ha?1 residue and (5) – control, were compared in subplots. In both plants, forage yield, potential quantum yield (Fv/Fm), chlorophyll a, total chlorophyll and carotenoid contents decreased significantly under drought stress. Chlorophyll a content, SPAD index and Fv/Fm were higher in corn than in sorghum, but RWC was higher in sorghum. Corn produced higher forage yield (62.8 t ha?1) than sorghum (49.3 t ha?1). The application of 10 t ha?1 zeolite with 4.5 t ha?1 residue increased most traits more than any of the other treatments, but the superabsorbent had no significant effect on the studied traits.  相似文献   

19.
The experiment was conducted in a 22nd cycle of rice-wheat rotation established in the eastern India with a randomized block designed with various combinations of inorganic and organic sources of nutrients like farm yard manure (FYM), paddy straw (PS), and green manure in rice crop only. Application of nitrogen, phosphorus, and potassium (NPK) and its combination with FYM, PS, and green manuring increased the grain yield of rice significantly. Rice yield declined only in control plots (?0.003 t ha?1 year?1), whereas positive yield trend was maintained in all the treatments. All organically amended plots showed a better uptake as well as use efficiencies of applied phosphorus (P) inputs over control. The apparent P balance showed positive value in control treatment over the years ranging from ?4.8 to 24.8 kg ha?1 year?1. The positive yield trend of rice was maintained due to buildup of P from various organic inputs.  相似文献   

20.
Abstract

The dramatic increases in rice productivity and cultivation intensity through the implementation of green revolution (GR) technology using high yielding varieties (HYVs) of rice and chemical fertilizers were not long lasting in Indonesia. The stagnancy of rice productivity in recent years without any scientific reasons presents a challenge for agronomists and soil scientists in Indonesia. This study describes the effects of long-term intensive rice cultivation on the change in available silica (Si) in sawah soil. The term sawah refers to a leveled and bounded rice field with an inlet and an outlet for irrigation and drainage. Soil samples collected by Kawaguchi and Kyuma in 1970 and new samples taken in 2003 from the same sites or sites close to the 1970 sites were analyzed and compared. From 1970 to 2003, the average content of available Si decreased from 1,512 ± 634 kg SiO2 ha?1 to 1,230 ± 556 kg SiO2 ha?1 and from 6,676 ± 3,569 kg SiO2 ha?1 to 5,894 ± 3,372 kg SiO2 ha?1 in the 0–20 cm and 0–100 cm soil layers, respectively. Cultivation intensity differences between seedfarms planted with rice three times a year and non-seedfarms rotating rice and upland crops appeared to affect the changing rates of available Si within the study period. In the 0–20 cm soil layer, the average content of available Si decreased from 1,646 ± 581 kg SiO2 ha?1 to 1,283 ± 533 kg SiO2 ha?1 (?22%) and from 1,440 ± 645 kg SiO2 ha?1 to 1,202 ± 563 kg SiO2 ha?1 (?17%) in seedfarms and non-seedfarms, respectively. Differences in topographical position also influenced the decreasing rate of available Si in this study. Using similar management practices and cultivation intensity, upland sampling sites lost more Si compared with lowland sites. Planted rice under a rain fed system with no Si addition from rain water in an upland position may be a reason for the higher loss of Si, particularly in non-seedfarms. The Si supply from irrigation water might have contributed to the slowdown in the decreasing rate of available Si in Java sawah soils.  相似文献   

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